4820-01-309-1713 (975XLS-3/4IN.)
4820-01-309-1713 is equivalent to manufacture part number 4777K21. It is a backflow prevente valve assembly and is classified under Federal Supply Class 4820 (4820 - Valves, Nonpowered), stocked for defense, aerospace, MRO, and industrial maintenance applications. This item is cataloged in the NATO supply system under 4820 - Valves, Nonpowered and is available through NSN-PARTS for U.S. government MRO, and commercial procurement.